The present invention generally relates to systems for subsurface fluid drainage and storage, and more particularly to a system and method for vertically stacking in a nested relation an apparatus especially suited for promoting, directing, and storing rain and irrigation water drainage on and/or below the land""s surface.
Most of the subsurface fluid and drainage and storage systems known are variations on a fundamental concept of providing lateral drainage through one or more layers of sorted gravel or crushed rock. In the typical known system, a layer of gravel underlies the smaller-particle root zone beneath the upper surface of soil. Water passing through the root zone reaches the gravel layer, and then presumably flows laterally through the gravel layer to a perforated pipe or French drain for discharge into a nearby surface watercourse or into a storm sewer system. Known systems however, are vulnerable over time as the gravel settles into an ever more densely packed layer. As fine sand filters down and fills voids in the gravel, the gravel layer""s fluid transmissivity is adversely affected. Additionally, gravel""s tendency to settle reduces the desirability of placing pipes within a gravel layer, as severe settling and compaction may lead to pipe rupture.
U.S. Pat. Nos. 5,250,340; 5,102,048; 5,848,856; and 5,123,778, the entire disclosures of which are hereby incorporated by reference, disclose additional systems that generally relate to the drainage and storage of fluid.
A subsurface fluid drainage and storage system with high void storage volume that is placed in compression, instead of bending or tension, that provides for very high loading. The dranage and storage system preferably is comprised of one or more mats nestably stacked upon each other. Each mat comprises crush-resistant support members each possessing a substantially open receiving end located near the top of the support member, a substantially open compression fitting located near the bottom of the support member, a plurality of ribs extending longitudinally along the inner sidewall of the support member, and at least one peripheral wall opening extending upward longitudinally from the bottom of the compression fitting and terminating above the compression fitting. The support members are held in spaced relation to one another by interior struts such that the interior struts and the support members define a grid. An exterior strut, operatively connected to at least one support member extends along the perimeter of the grid to provide added support. The compression fitting allows the mats to be vertically stacked in a nested relation and thereby provides increased strength against lateral forces, relatively compact construction, larger storage volume, ease of transport, and ready installation. Additionally, the system may be encased by an impervious liner to allow the system to store water.
There has thus been outlined certain features of the invention in order that the detailed description that follows may be better understood. There are additional features of the invention that will be described which will form the subject matter of the claims appended. It is to be understood that the invention is not limited in its application to the details of construction and to the arrangements of the components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced and carried out in various ways. Also, it is to be understood that the phraseology and terminology employed are for the purpose of description and should not be regarded as limiting. As such those skilled in the art will appreciate that the conception, upon which this disclosure is based, may readily be utilized as a basis for the designing of other structures, methods, and systems for carrying out the several purposes of the present invention. It is important therefore, that the claims be regarded as including such equivalent constructions insofar as they do not depart from the spirit and scope of the present invention.